In the telecommunications industry, high-density adapter blocks are used to accommodate the demand for increased fiber optic transmissions. The adapter blocks are typically mounted to a panel fixture. The adapter blocks generally include a number of adapters to which fiber optic cables are terminated. Cable management of such systems requires accessibility to the cable fiber terminations at the adapters. To facilitate accessibility, some panel fixtures and adapter blocks have a slide mount that allows a technician to slide an adapter block away from the other blocks for access to the densely packed terminations of the adapter block. Other panel fixtures and adapter blocks have a threaded fastener mount that allows a technician to remove an adapter block from the panel fixture for access. Further development in such fiber termination arrangements is desired.